core: Get platform memory map and exit boot services

Signed-off-by: Ian M. <ian@aptel.org>

1 files changed, 63 insertions, 0 deletions

diff --git a/core/memmap.c b/core/memmap.c
new file mode 100644
index 0000000..f02e538
--- /dev/null
+++ b/core/memmap.c
@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2026, Apollo Telephone Laboratories.
+ * Provided under the BSD-3 clause.
+ */
+
+#include <sboot/memmap.h>
+
+EFI_STATUS
+SBootGetMemmap(OUT PLATFORM_MEMMAP *Map)
+{
+    EFI_STATUS Status;
+
+    if (Map == NULL) {
+        return EFI_INVALID_PARAMETER;
+    }
+
+    Map->Map = NULL;
+    Map->MapSize = 0;
+    Map->MapKey = 0;
+    Map->DescriptorSize = 0;
+    Map->DescriptorVersion = 0;
+
+    Status = uefi_call_wrapper(
+        gBS->GetMemoryMap,
+        5,
+        &Map->MapSize,
+        Map->Map,
+        &Map->MapKey,
+        &Map->DescriptorSize,
+        &Map->DescriptorVersion
+    );
+
+    Map->Map = AllocatePool(Map->MapSize);
+    if (Map->Map == NULL) {
+        return EFI_OUT_OF_RESOURCES;
+    }
+
+    /*
+     * We have to call this twice as the act of allocating memory
+     * alters the memory map.
+     */
+    for (UINTN Idx = 0; Idx < 2; ++Idx) {
+        Status = uefi_call_wrapper(
+            gBS->GetMemoryMap,
+            5,
+            &Map->MapSize,
+            Map->Map,
+            &Map->MapKey,
+            &Map->DescriptorSize,
+            &Map->DescriptorVersion
+        );
+
+        if (!EFI_ERROR(Status)) {
+            break;
+        }
+    }
+
+    if (EFI_ERROR(Status)) {
+        Print(L"fatal: failed to get memory map\n");
+    }
+
+    return EFI_SUCCESS;
+}